Electrophotography refers to producing photographic images by electrical means, and xerography is a form of electrophotography for copying documents and other graphic matter. Xerographic copiers are extensively used in a variety of environments, such as offices, libraries, and educational institutions.
The basic elements of a xerographic copier are well known to those skilled in the art. A light source forms an electrostatic latent image of an original document on a photosensitive medium. The photosensitive medium, as it moves within the copier, travels adjacent a source of tiny plastic particles called toner. The electrostatic force of the latent image on the photosensitive medium attracts the toner, thereby providing a developed image of toner particles on the surface of the photosensitive medium. The toner image is transferred through electrostatic charges to an image receptor, which is normally a sheet of paper or plastic. The image receptor then passes through a heating device which melts the toner particles, thereby fixing or fusing the image of the original onto the image receptor.
After the toner image is transferred to the image receptor, some toner particles remain clinging to the surface of the photosensitive medium. Furthermore, toner is a fine powder and some toner particles become airborne within the xerographic copier and cling to the surface of the photosensitive medium as the copier operates. A cleaning station, set up adjacent to the photosensitive medium, removes the clinging toner before the next image is formed. Otherwise, the clinging toner would contaminate subsequent images formed on the photosensitive medium.
As is well known in the prior art, the cleaning station gradually becomes filled with toner and that toner must be removed. In order to remove the toner from a cleaning station, the cleaning station must be removed from the xerographic copier. In conventional xerographic copiers, access to the cleaning station is difficult. As a result, it is difficult to remove the cleaning station without spilling toner into the copier as the cleaning station is removed. The toner tends to become airborne when spilled, and this airborne toner settles throughout the copier, contaminating images formed on the photosensitive medium and causing abrasive damage to various moving parts.
As is also well known in the prior art, the cleaning element of the cleaning station gradually degrades and must be replaced. In conventional xerographic copiers, the cleaning station must be removed to replace the cleaning element. Therefore, the same problems discussed above are encountered when replacing the cleaning element.
More recently, laser printers have become popular office machines. As is known to those skilled in the art, laser printers are usually constructed with print engines which are similar to those used in xerographic copiers. A raster-scanned laser beam creates the latent image directly on the photosensitive medium in a laser printer. After the image is created on the photosensitive medium, the printing process is similar to that in a xerographic copier.
Therefore, there is a need in electrophotographic print engines or laser print engines for a cleaning station which is simpler to clean, remove, and replace without damaging other internal parts.